Color filter, method of making the same, and display device including the same

ABSTRACT

A color filter including a first region configured to emit a first light, a second region configured to emit a second light having a longer wavelength than a wavelength of the first light, a third region configured to emit a third light having a longer wavelength than the wavelength of the second light, a first layer including two or more quantum dots, and a second layer formed on at least one surface of the first layer, wherein the first layer and the second layer are disposed in at least the second region and the third region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/206,718, filed on Jul. 11, 2016, which claims priority to and thebenefit of Korean Patent Application No. 10-2015-0180233, filed in theKorean Intellectual Property Office on Dec. 16, 2015, and all thebenefits accruing therefrom under 35 U.S.C. § 119, the contents of whichin their entirety are herein incorporated by reference.

BACKGROUND 1. Field

The described technology relates to a color filter, a manufacturingmethod thereof, and a display device including the color filter.

2. Description of the Related Art

A liquid crystal display device (LCD) implements a color by transmittingpolarized light which has passed through a liquid crystal layer throughan absorptive color filter. The LCD has a viewing angle which is narrowand luminance which is lowered due to low light transmittance of theabsorptive color filter. However, when a photoluminescent type of colorfilter replaces the absorptive color filter, the viewing angle thereofmay be widened and the luminance thereof may be improved.

However, in the case of such a photoluminescent type of color filter, aluminous efficiency deterioration phenomenon has been reported. That is,luminous efficiency of a manufactured photoluminescent type of colorfilter does not reach that of an initially designed idealphotoluminescent type of color filter. Therefore, it is desirable todevelop a technique that may minimize the luminous efficiencydeterioration phenomenon in a manufacturing process of thephotoluminescent type of color filter.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the describedtechnology and therefore it may contain information that does not formthe prior art that is already known in this country to a person ofordinary skill in the art.

SUMMARY

An exemplary embodiment provides a color filter including a first regionconfigured to emit a first light, a second region configured to emit asecond light that has a longer wavelength than a wavelength of the firstlight, a third region configured to emit a third light that has a longerwavelength than the wavelength of the second light, a first layerincluding two or more quantum dots, and a second layer disposed on atleast one surface of the first layer, wherein the first layer and thesecond layer are disposed in at least the second region and the thirdregion.

The second layer may have light transmittance of greater than or equalto about 80% with respect to the first light.

The first light may be blue light.

A thickness of the second layer may be in a range of about 10% to about60% of a thickness of the first layer.

Each of the first layer and the second layer may include aphotosensitive resin.

The first layer may further include a light diffusing agent selectedfrom a metal oxide particle, a metal particle, and a combinationthereof.

The quantum dots may include a Group II-VI compound, a Group III-Vcompound, a Group IV-VI compound, a Group IV compound, a Group II-III-VIcompound, a Group I-II-IV-VI compound, or a combination thereof.

The quantum dots may include a plurality of first quantum dots disposedin the second region and configured to emit the second light having alonger wavelength than the wavelength of the first light by absorbingthe first light, and a plurality of second quantum dots disposed in thethird region and configured to emit the third light having a longerwavelength than the wavelength of the first light and the wavelength ofthe second light by absorbing the first light.

The first region is includes a transparent body.

Another embodiment provides a method of manufacturing the color filter,the method including forming the first layer on a substrate, forming thesecond layer on the first layer to obtain a stacked body in which thefirst layer and the second layer are disposed on the substrate,pre-baking the stacked body, patterning the stacked body to obtain apatterned stacked body, and post-baking the patterned stacked body.

The pre-baked stacked body has a first retention of about 70% to about100%, wherein the first retention is a percentage of a light conversionrate of the post-baked stacked body with respect to a light conversionrate of the pre-baked stacked body.

The manufacturing method of the color filter may further include agingthe stacked body.

The aged stacked body has a second retention of about 85% to about 100%,wherein the second retention is a percentage of a light conversion rateof the aged stacked body with respect to a light conversion rate of thepre-baked stacked body.

The aged stacked body has a third retention of about 100% to about 120%,wherein the third retention is a percentage of a light conversion rageof the aged stacked body with respect to a light conversion rate of thepost-baked stacked body.

Yet another embodiment provides a display device including the colorfilter, the display device including a light source configured to emitthe first light in a first direction, a first substrate disposed infront of the light source in the first direction, the color filterdisposed in front of the first substrate in the first direction, and asecond substrate disposed in front of the color filter in the firstdirection, wherein in the color filter the first layer is disposed infront of the second layer in the first direction.

The display device may further include a liquid crystal layer interposedbetween the first substrate and the color filter or between the colorfilter and the second substrate.

Accordingly, the luminous efficiency deterioration which may occur in amanufacturing process of the color filter may be minimized, and a colorfilter having excellent luminous efficiency may be provided.

Further, by including the color filter in the display device, both theviewing angle and the luminous efficiency with respect to powerconsumption of a liquid crystal display device, may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, advantages and features of this disclosurewill become more apparent by describing in further detail exemplaryembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic illustration showing an effect of a second layerin a color filter on ameliorating luminous efficiency deteriorationaccording to an exemplary embodiment;

FIG. 2 is an illustration of the color filter in FIG. 1;

FIG. 3 is a cross-sectional illustration of a display device includingthe color filter of FIG. 2; and

FIG. 4 is a flowchart showing a method of manufacturing the color filterof FIG. 2.

DETAILED DESCRIPTION

Hereinafter, the described technology will be described more fully withreference to the accompanying drawings, in which exemplary embodimentsare shown. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the described technology.

In the drawings, the thicknesses of layers, films, panels, regions,etc., are exaggerated for clarity. Like reference numerals designatelike elements throughout the specification. It will be understood thatwhen an element such as a layer, film, region, or substrate is referredto as being “on” another element, it can be directly on the otherelement or intervening elements may also be present. In contrast, whenan element is referred to as being “directly on” another element, thereare no intervening elements present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that, although the terms “first,” “second,”“third,” etc. may be used herein to describe various elements,components, regions, layers, and/or sections, these elements,components, regions, layers, and/or sections should not be limited bythese terms. These terms are only used to distinguish one element,component, region, layer, or section from another element, component,region, layer, or section. Thus, “a first element,” “component,”“region,” “layer,” or “section” discussed below could be termed a secondelement, component, region, layer, or section without departing from theteachings herein.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, or 5% of the statedvalue.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Quantum dots (QD) may be applied to various display devices as a complexin which quantum dots are dispersed in a polymer host matrix. Thequantum dots may be employed in a light emitting diode (LED) or the likeas a light converting layer by being dispersed in a host matrix formedof a polymer or an inorganic material. In the case of the quantum dots,it is possible to uniformly adjust particle sizes and relatively freelyadjust the particle sizes in colloid synthesis. When the particle sizesof the quantum dots are equal to or less than about 10 nanometers (nm),a quantum confinement effect indicating that an energy band gapincreases as the size decreases becomes prominent, thereby increasingenergy density. Since the quantum dots may have theoretical quantumefficiency (QY) of about 100% and may emit light at a high color purity(e.g., a full width half maximum (FWHM) of about 40 nm or less), theyimprove light emitting efficiency and color reproducibility.Accordingly, the quantum dots may be applied to diverse display devices,if they can be patterned. Further, among such diverse applications, theymay contribute to development of a high quality photoluminescent type ofLCD in the case of being employed for a color filter of the LCD.

Hereinafter, a part of a color filter in which a first layer and asecond layer are formed according to an exemplary embodiment will beschematically described, and an effect of ameliorating luminousefficiency deterioration by the schematic structure of the first layerand the second layer will be described.

FIG. 1 schematically illustrates the ameliorating effect of the secondlayer in the color filter on the luminous efficiency deteriorationaccording to the exemplary embodiment.

Referring to FIG. 1, a color filter 100 is a stacked structure includinga first layer 10 and a second layer 20 disposed on at least one surfaceof the first layer 10. The first layer 10 includes two or more quantumdots 11, and the quantum dots 11 are dispersed in the first layer 10.

Since the quantum dots 11 have an isotropic radiation characteristic,the quantum dots 11 may radiate light in a radial direction when anenergy state of the quantum dots is excited (e.g. elevated in energy) byincident light received from a light source and then returned to aground state. Therefore, the first layer 10 including the quantum dots11 may be employed as a light emitting layer. In FIG. 1, a double-linedarrow represents a path of incident light, and a solid-lined arrowrepresents a path of radiated light.

Since the quantum dots 11 have a discrete energy band gap caused by aquantum confinement effect, the quantum dots 11 may radiate light havinga certain wavelength range by receiving the incident light. Accordingly,since the first layer 10 includes two or more of the quantum dots 11,the first layer 10 according to the present exemplary embodiment maydisplay an image at higher color purity than the first layer including adifferent light emitting material.

The first layer 10 may further include light diffusing agents 12. Thelight diffusing agents 12 may be dispersed in the first layer 10together with the quantum dots 11. The light diffusing agents 12 mayguide the incident light to the quantum dots 11 or may guide the lightradiated from the quantum dots 11 outside of the first layer 10.Accordingly, luminous efficiency deterioration of the first layer 10 maybe minimized. In FIG. 1, a two-point chain lined arrow represents a pathof light guided by the light diffusing agents 12.

For example, the second layer 20 may be disposed on one surface of thefirst layer 10, serving as an incident surface into which the incidentlight is introduced as shown in FIG. 1, but it is not limited thereto.Alternatively, the second layer 20 may be disposed on each of oppositesurfaces of the first layer 10.

The second layer 20 may be formed of an optically transparent material.For example, the second layer 20 may be formed of a material havingexcellent light transmittance for a certain wavelength range.

For example, when the incident light illustrated in FIG. 1 is blue lightthat has a wavelength range of about 500 nanometers (nm) or less, thesecond layer 20 may be formed of a material having excellent lighttransmittance for a wavelength range of about 500 nm or more. Forexample, the second layer 20 may be formed of a material having lighttransmittance of about 80% or more, about 85% or more, or about 90% ormore, for light having the wavelength range of about 500 nm or less.

Further, for example, the second layer 20 may be formed to have asimilar refractive index to that of the first layer 10. Accordingly, acase where the incident light introduced into the second layer 20 isreflected or scattered by the second layer 20 may be minimized. In otherwords, an optical loss generated at an interface between the secondlayer 20 and the first layer 10 may be minimized.

In the present exemplary embodiment, the second layer 20 is formed as asingle layer on the first layer 10 as shown in FIG. 1, but the presentexemplary embodiment is not limited thereto. For example, the secondlayer 20 may be formed as a multilayer including two or more layers.

In the present exemplary embodiment, the second layer 20 may reflectsome of the radiated light, which returns toward the light source due toan isotropic radiation characteristic of the quantum dots 11, to guideit in an opposite direction to that of the second layer 20. In FIG. 1, aone-point chain lined arrow represents a path of reflected light whichis reflected by the second layer 20, and a dash lined arrow represents apath of transmitted light, which returns to the light source by beingtransmitted through the second layer 20.

For example, when the second layer 20 is interposed between the firstlayer 10 and the light source as in the present exemplary embodiment,light-recycling of the radiated light may be possible by reflecting someof the radiated light, which returns toward the light source due to theisotropic radiation characteristic of the quantum dots 11, therebyallowing the light to remain in the first layer 10 by guiding it in theopposite direction to that of the second layer 20, or the like. As aresult, the second layer 20 may serve as an optical barrier layer thatcompensates for the luminous efficiency of the first layer 10, e.g., thelight emitting layer. Accordingly, it is possible to provide a colorfilter that may minimize luminous efficiency deterioration.

A thickness of the second layer 20 may be in a range of about 5% toabout 100%, or about 10% to about 60%, of the thickness of the firstlayer 10.

When the second layer 20 has a thickness that is less than about 5% ofthe thickness of the first layer 10, the ameliorating effect of theluminous efficiency deterioration of the first layer 10 by the action ofthe second layer 20 may be insignificant, and when the second layer 20has a thickness exceeding about 100% of the thickness of the first layer10, a light loss of the incident light due to the action of the secondlayer 20 may be increased. However, the aforementioned light-recyclingof the radiated light by the action of the second layer 20 may beeffectively performed by forming the second layer 20 to have thethickness in the above-described range.

Hereinafter, materials of the first layer 10 and the second layer 20 inthe color filter 100 according to the present exemplary embodiment willbe described.

In the present exemplary embodiment, each of the first layer 10 and thesecond layer 20 may be formed of a photosensitive resin. Accordingly,the color filter 100 may be readily patterned by a photolithographicmethod.

In the present exemplary embodiment, the photosensitive resins used toform the first layer 10 and the second layer 20 may each include abinder, a photopolymerization monomer including a carbon-carbon doublebond, a photoinitiator, a solvent, and a curing agent in common.

In the present exemplary embodiment, the binder may be a carboxylicbinder including a carboxyl group (—COOH). For example, the binder maybe a copolymer of a monomer mixture that includes a first monomerincluding the carboxyl group and the carbon-carbon double bond, and asecond monomer including the carbon-carbon double bond and a hydrophobicmoiety but not a carboxyl group. The quantum dots 11 are dispersed,e.g., spaced apart from each other, in the first layer 10 by the binderincluding a carboxyl group to form a quantum dot-polymer complexstructure.

For example, the first monomer may include a compound including acarboxylic acid, an ethylenically unsaturated group such as acrylicacid, methacrylic acid, maleic acid, itaconic acid, fumaric acid,3-butenoic acid, vinyl acetate, vinyl benzoic acid, or the like, but itis not limited thereto. The first monomer may include one or morecompounds.

For example, the second monomer may include an alkenyl aromatic compoundsuch as styrene, alpha-methyl styrene, vinyl toluene, vinyl benzylmethyl ether, or the like; an unsaturated carboxylic acid ester compoundsuch as methyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, butyl acrylate, butyl methacrylate, benzyl acrylate,benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,phenyl acrylate, phenyl methacrylate, or the like; an unsaturatedcarboxylic acid amino alkyl ester compound such as 2-amino ethylacrylate, 2-amino ethyl methacrylate, 2-dimethyl amino ethyl acrylate,N-phenylmaleimide, N-benzylmaleimide, N-alkylmaleimide, 2-dimethyl aminoethyl methacrylate, or the like; an unsaturated carboxylic acid glycidylester compound such as glycidyl acrylate, glycidyl methacrylate, or thelike; a cyano-substituted vinyl compound such as acrylonitrile,methacrylonitrile, or the like; and an unsaturated amide compound suchas acrylamide, methacrylamide, or the like, but it is not limitedthereto. One or more compounds may be employed as the second monomer.

The photoinitiator initiates photopolymerization between the abovephotopolymerization monomers. In the present exemplary embodiment, thephotoinitiator may include a triazine-based compound, anacetophenone-based compound, a benzophenone-based compound, athioxanthone-based compound, a benzoin-based compound, an oxime-basedcompound, or a combination thereof, but is not limited thereto.

Examples of the triazine-based compound may include2,4,6-trichloro-s-triazine,2-phenyl-4,6-bis(trichloromethyl)-s-triazine,2-(3′,4′-dimethoxy-styryl)-4,6-bis(trichloromethyl)-s-triazine,2-(4′-methoxy-naphthyl)-4,6-bis(trichloromethyl)-s-triazine,2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine,2-biphenyl-4,6-bis(trichloromethyl)-s-triazine,bis(trichloromethyl)-6-styryl-s-triazine,2-(naphtho-1-il)-4,6-bis(trichloromethyl)-s-triazine,2-(4-methoxy-naphtho-1-il)-4,6-bis(trichloromethyl)-s-triazine,2,4-trichloromethyl(piperonyl)-6-triazine, or2,4-(trichloromethyl(4′-methoxystyryl)-6-triazine, but they are notlimited thereto.

Examples of the acetophenone-based compound may include2,2′-diethoxyacetophenone, 2,2′-dibutoxyacetophenone,2-hydroxy-2-methylpropiophenone, p-t-butyl trichloroacetophenone,p-t-butyl dichloroacetophenone, 4-chloroacetophenone,2,2′-dichloro-4-phenoxy acetophenone,2-methyl-1-(4-(methylthio)phenyl)-2-morpholino propane-1-on,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-on, or the like,but they are not limited thereto.

Examples of the benzophenone-based compound may include benzophenone,benzoyl benzoic acid, benzoyl benzoic acid methyl, 4-phenylbenzophenone, hydroxy benzophenone, acrylic-benzophenone,4,4′-bis(dimethylamino)benzophenone, 4,4′-dichlorobenzophenone,3,3′-dimethyl-2-methoxy benzophenone, or the like, but they are notlimited thereto.

Examples of the thioxanthone-based compound may include thioxanthone,2-methyl thioxanthone, isopropylthioxanthone, 2,4-diethyl thioxanthone,2,4-diisopropyl thioxanthone, 2-chloro thioxanthone, or the like, butthey are not limited thereto.

Examples of the benzoin-based compound may include benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoinisobutyl ether, benzyl dimethyl ketal, or the like, but they are notlimited thereto.

Examples of the oxime-based compound may include2-(o-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octandione or1-(o-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-il]ethanone,but they are not limited thereto.

In addition to the above photoinitiator, a carbazole-based compound, adiketone-based compound, a sulfonium borate-based compound, adiazo-based compound, a biimidazole-based compound, or the like, or acombination thereof may be employed as the photoinitiator.

In the present exemplary embodiment, a photosensitive composition mayinclude diverse additives such as a leveling agent, a coupling agent,and the like. An amount of the additives is not particularly limited,and may be appropriately adjusted by a skilled person without undueexperimentation to be within a range which does not adversely affect thephotosensitive composition or a pattern formed therefrom.

The leveling agent serves to prevent the formation of stains and spotsin a film and to improve a leveling characteristic of the film. Detailedexamples of the leveling agent will be described as follows, but theyare not limited thereto.

The examples of the leveling agent may include a commercial product of afluorine-based leveling agent such as BM-1000®, BM-1100®, or the like(BM Chemie Group); MEGAFACE F 142D®, MEGAFACE F 172®, MEGAFACE F 173®,MEGAFACE F 183®, or the like (Dainippon Ink Kagaku Kogyo Co., Ltd.);FULORAD FC-135®, FULORAD FC-170C®, FULORAD FC-430®, FULORAD FC-431®, orthe like (Sumitomo 3M Co., Ltd.); SURFLON S-112®, SURFLON S-113®,SURFLON S-131®, SURFLON S-141®, SURFLON S-145®, or the like (Asahi GlassCo., Ltd.); or SH-28PA®, SH-190®, SH-193®, SZ-6032®, SF-8428®, or thelike (Toray Silicone Co., Ltd.).

The leveling agent may be readily adjusted by a skilled person withoutundue experimentation depending on a desired property.

The coupling agent serves to improve adhesion to the substrate, and mayinclude a silane-based coupling agent. Detailed examples of thesilane-based coupling agent may include vinyl trimethoxysilane, vinyltris(2-methoxyethoxysilane), 3-glycidoxypropyltrimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane,3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,or the like, or a combination thereof may be used.

In the present exemplary embodiment, the amount of the solvent may beappropriately adjusted in consideration of the amounts of theaforementioned elements (the binder, the photopolymerization monomer,the photoinitiator, and the additives) and/or amounts of the quantumdots 11, and the light diffusing agents 12, which will be describedlater.

Specifically, the amount of the solvent is the amount of thephotosensitive resin excluding the amount of a solid component(non-volatile component), and may be appropriately adjusted inconsideration of the compatibility of the solvent with other components(e.g., the binder, the photopolymerization monomer, the photoinitiator,the additives, and/or the quantum dots and light diffusing agent),compatibility of the solvent with an alkali development solution, aboiling temperature of the solvent, and the like. Examples of thesolvent may include an ethylene glycol compound such as ethyl3-ethoxypropionate, ethylene glycol, diethylene glycol, polyethyleneglycol, or the like; a glycol ether compound such as ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, diethylene glycolmonomethyl ether, ethylene glycol diethyl ether, diethylene glycoldimethyl ether, or the like; a glycol ether acetate compound such asethylene glycol acetate, ethylene glycol monoethyl ether acetate,diethylene glycol monoethyl ether acetate, diethylene glycol monobutylether acetate, or the like; a propylene glycol compound such aspropylene glycol or the like; a propylene glycol ether compound such aspropylene glycol monomethyl ether, propylene glycol monoethyl ether,propylene glycol monopropyl ether, propylene monobutyl ether, propyleneglycol dimethyl ether, dipropylene glycol dimethyl ether, propyleneglycol diethyl ether, dipropylene glycol diethyl ether, or the like; apropylene glycol ether acetate compound such as propylene glycolmonomethyl ether acetate, dipropylene glycol monoethyl ether acetate, orthe like; an amide compound such as N-methylpyrrolidone,dimethylformamide, dimethylacetamide, or the like; a ketone compoundsuch as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK),cyclohexanone, or the like; a petroleum compound such as toluene,xylene, solvent naphtha, or the like; an ester compound such as ethylacetate, butyl acetate, ethyl lactate, or the like; an ether compoundsuch as diethyl ether, dipropyl ether, dibutyl ether, or the like; and acombination thereof.

In the present exemplary embodiment, the curing agent may include athiol-based curing agent. The thiol-based curing agent may be a compoundincluding one or more thiol groups that react with the carbon-carbondouble bond of the photopolymerization monomer and which reactsprimarily with the photopolymerization monomer during a heat-curingprocess.

In the present exemplary embodiment, the thiol-based curing agent is notparticularly limited as long as it includes at least one thiol group inits molecular structure.

In the present exemplary embodiment, examples of the thiol curing agentmay include ethoxylated trimethylolpropane tris(3-mercaptopropionate),trimethylolpropane tris(3-mercaptopropionate), glycoldi(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate),4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, pentaerythritoltetrakis(3-mercaptoacetate), trimethylol propanetris(3-mercaptoacetate), 4-t-butyl-1,2-benzenedithiol,2-mercaptoethylsulfide, 4,4′-thiodibenzenethiol, benzenedithiol, glycoldimercaptoacetate, glycol dimercaptopropionate ethylenebis(3-mercaptopropionate), polyethylene glycol dimercaptoacetate,polyethylene glycol di(3-mercaptopropionate), or the like, or acombination thereof.

The thiol curing agent may primarily serve to heat-cure thephotosensitive resin during a pre-baking step or the like, and may alsoserve, for example, to prevent damage to the quantum dots inside thephotosensitive resin of which the first layer is formed throughout anentire process of manufacturing the color filter.

The photosensitive resin for forming the first layer 10 may furtherinclude the aforementioned quantum dots 11 and light diffusing agents 12in addition to the above components. As a result, the first layer 10 mayhave a light emitting characteristic since the first layer 10 furtherincludes the quantum dots 11, and the ameliorating effect of the firstlayer 10 on the luminous efficiency deterioration may be improved sincethe first layer 10 further includes the light diffusing agents 12.

In the present exemplary embodiment, the quantum dots 11 are notparticularly limited, and any known or commercially available quantumdots may be employed.

For example, the quantum dots 11 may include a Group II-VI compound, aGroup III-V compound, a Group IV-VI compound, a Group IV compound, aGroup II-III-VI compound, a Group I-II-IV-VI compound, or a combinationthereof, wherein each Group refers to a Group of the Periodic Table ofthe Elements.

For the Group II-VI compound, a binary compound selected from CdSe,CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and acombination thereof; a ternary compound selected from CdSeS, CdSeTe,CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe,CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, anda combination thereof; or a quaternary compound selected from HgZnTeS,CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS,HgZnSeTe, HgZnSTe, and a combination thereof, may be employed. For theGroup III-V compound, a binary compound selected from GaN, GaP, GaAs,GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and a combinationthereof; a ternary compound selected from GaNP, GaNAs, GaNSb, GaPAs,GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs,InPSb, and a combination thereof; or a quaternary compound selected fromGaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb,GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and acombination thereof, may be employed. For the Group IV-VI compound, abinary compound selected SnS, SnSe, SnTe, PbS, PbSe, PbTe, and acombination thereof; a ternary compound selected from SnSeS, SnSeTe,SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and a combinationthereof; or a quaternary compound selected from SnPbSSe, SnPbSeTe,SnPbSTe, and a combination thereof, may be employed. Examples of theGroup I-III-VI compound may include CuInSe2, CuInS2, CuInGaSe, orCuInGaS, or a combination thereof, but they are not limited thereto.Examples of the Group I-II-IV-VI compound may include CuZnSnSe, CuZnSnS,or a combination thereof, but they are not limited thereto. For theGroup IV compound, a unary compound selected from Si, Ge, and acombination thereof; and a binary compound selected from SiC, SiGe, anda combination thereof, may be employed.

The binary compound, the ternary compound, or the quaternary compoundmay exist in a uniform concentration or in a partially differentconcentration in the quantum dot particles.

In the present exemplary embodiment, the quantum dots may have acore/shell structure in which one quantum dot surrounds another quantumdot. An interface between a core and a shell may have a concentrationgradient such that a concentration of an element in the shell decreasestoward a center of the quantum dot. Further, the quantum dots may have astructure including a semiconductor nanocrystal core and a multi-layeredshell which surrounds the semiconductor nanocrystal core. In this case,the multi-layered shell may have two or more layers each of which mayinclude a single composition or an alloy, or a concentration gradient.

Further, the quantum dots may have a structure in which a composition ofthe shell has a larger energy band gap than that of the core, therebyenhancing the quantum confinement effect. Also in the case of themulti-layered shell, the composition of an outer shell may have a largerenergy band gap than that of an inner shell. In this case, the quantumdots may have a wavelength excitation range from an ultraviolet regionto an infrared region.

The quantum dots may have a quantum efficiency of about 10% or more, forexample, about 30% or more, about 50% or more, about 60% or more, about70% or more, or about 90% or more.

Further, the quantum dots may have a narrow spectrum to improve colorpurity or color reproducibility of the display device. The quantum dotsmay have a full width at half maximum (FWHM) of a light emittingspectrum of about 45 nm, or, for example, about 40 nm or more, or about30 nm or more. In this range, the color purity and the colorreproducibility of the display device may be improved.

The quantum dots 11 are spherically illustrated in FIG. 1 forconvenience of illustration, but are not limited thereto. The quantumdots 11 may have any general shape in the art and are not particularlylimited. For example, the quantum dots may be a nanoparticle having aspherical shape, a pyramid shape, a multi-arm shape, or a cube shape, ormay be a nanotube shape, a nanowire shape, a nanofiber shape, or ananosheet shape.

The quantum dots may have a diameter that is in a range of about 1 nm toabout 100 nm. For example, in the present exemplary embodiment, thequantum dots may have a diameter that is in a range of about 1 nm toabout 20 nm, for example, about 2 nm to about 15 nm, or about 3 nm toabout 15 nm. In the case where the quantum dots have a non-sphericalshape, the diameter refers to the furthest distance between two pointson the quantum dots.

The light diffusing agents 12 may minimize the luminous efficiencydeterioration due to the isotropic radiation characteristic in the firstlayer 10, since the light diffusing agents 12 diffuse the incident lightin various directions in the first layer 10 as described above. Thelight diffusing agents 12 may include inorganic oxide particles such asalumina particles, silica particles, zirconia particles, zinc oxideparticles, titanium oxide particles, or metal particles such as goldparticles, silver particles, copper particles, platinum particles, or acombination thereof, but they are not limited thereto.

As such, the first layer 10 and the second layer 20 according to thepresent exemplary embodiment include a photosensitive material formed ofthe above-described photosensitive resin. Accordingly, aphotolithographic pattern formed of a quantum dot-polymer complex can bereadily formed by the photolithographic method, even when the quantumdots 11 do not include a photopolymerization functional group (e.g., thecarbon-carbon double bond such as methacrylate, acrylate, or the like).Further, a surface treatment of the quantum dot may be omitted, and useof an organic solvent may be excluded when a development process, whichwill be described later, is performed.

Hereinafter, a detailed structure of the color filter 100 according toan exemplary embodiment will be described with reference to FIG. 2.

FIG. 2 specifically illustrates the color filter of FIG. 1.

In the present exemplary embodiment, the color filter 100 may be dividedinto a first region PX1 for displaying first light, a second region PX2for displaying second light, and a third region PX3 for displaying thirdlight. Each region is separated by light blocking members 403. Further,the first region PX1, the second region PX2, and the third region PX3are regularly arranged in a predetermined form. For example, in adirection from a left side to a right side in FIG. 2, an arrangement inwhich the first region PX1, the third region PX3, and the second regionPX2 are sequentially disposed is referred to as one unit region. Two ormore unit regions may be regularly and repeatedly arranged. Further,such unit regions may be repeatedly arranged in a two dimensional form,e.g., in a matrix shape. However, the arrangement sequence, direction,and the like of the first region PX1 to the third region PX3 may bediversely determined.

In the present exemplary embodiment, in the color filter 100, the firstregion PX1 may display blue light as the first light, the second regionPX2 may display green light as the second light, and the third regionPX3 may display red light as the third light.

The color filter 100 may be a “blue-light color filter” that displaysblue light, green light, and red light by receiving the first light. Asa result, the first layer 10 and the second layer 20 may not be formedin the first region PX1 that displays blue light, and may instead beformed in each of the second region PX2 and the third region PX3. Thefirst region PX1 may be filled with transparent bodies.

However, an operation of the color filter and a configuration dependingon the operation are not limited thereto, and the color filter maydisplay blue light, green light, and red light by receiving white lightor ultraviolet light. In this case, the first layer 10 and the secondlayer 20 may be formed in each of the first region PX1 to the thirdregion PX3.

Hereinafter, the color filter 100 according to the present exemplaryembodiment will be described using the “blue-light color filter” as anexample for convenience of description. A blue filter 10 b designates atransparent body that is filled in the first region PX1, a green filter10 g designates the first layer formed in the second region PX2, a greenbarrier layer 20 g designates the second layer formed in the secondregion PX2, a red filter 10 r designates the first layer formed in thethird region PX3, and a red barrier layer 20 r designates the secondlayer formed in the third region PX3.

The first region PX1 includes the blue filter 10 b. The blue filter 10 bmay be formed of the transparent body and the quantum dots are notincluded therein. The blue filter 10 b thus displays the blue light thatis incident light by emitting the blue light.

The transparent bodies may fill the first region PX1 as shown in FIG. 2,but may have various heights, sizes, or the like depending on exemplaryembodiments. The transparent bodies may include scattering-inducedparticles that change a projecting direction of the blue light, whilemaintaining a wavelength thereof as unchanged. Alternatively, thetransparent bodies may be omitted depending on exemplary embodiments. Inthis case, a hollow space may be formed in the first region PX1, and thehollow space may serve as the blue filter 10 b.

Meanwhile, the second layer 20 may not be formed in the first regionPX1. This is because, in the case of the exemplarily describedblue-light color filter, it is difficult to expect a light-recyclingeffect by the action of the second layer 20. However, in the case thatthe color filter 100 of the present exemplary embodiment is a whitefilter of an ultraviolet filter, the first layer 10 b including thequantum dots which radiate the blue light and the second layer forminimizing the luminous efficiency deterioration of the first layer maybe formed in the first region PX1 instead of the aforementionedtransparent bodies.

The second region PX2 includes the green filter 10 g and the greenbarrier layer 20 g. The green filter 10 g includes first quantum dots 11a that radiate the green light when the energy states of the quantumdots 11 a are excited by receiving blue incident light and return to theground state. Since some of the radiated green light is reflected by thegreen barrier layer 20 g, a projecting passing direction of the radiatedgreen light is changed so that the reflected light is radiated outsidethe green filter 10 g, and thus the reflected light displays a greencolor. Accordingly, the luminous efficiency deterioration of the greenlight displayed in the second region PX2 may be minimized.

The third region PX3 includes the red filter 10 r and the red barrierlayer 20 r. The red filter 10 r includes second quantum dots 11 b thatradiate the red light when the energy states of the second quantum dots11 b are excited by receiving the blue incident light and return to theground state. Since some of the radiated red light is reflected by thered barrier layer 20 r, a projecting passing direction of the radiatedred light is changed so that the reflected light is radiated outside thered filter 10 r, and thus the reflected light displays a red color.Accordingly, the luminous efficiency deterioration of the red lightdisplayed in the third region PX3 may be minimized.

Meanwhile, the first quantum dots 11 a and the second quantum dots 11 bare formed of the same material, while having different sizes from eachother in order to radiate lights having different wavelengths, e.g., thegreen light and the red light.

For example, the first quantum dots 11 a may have a smaller size (e.g.diameter) than those of the second quantum dots 11 b in order to radiategreen light of a relatively high energy. For example, the first quantumdots 11 a may have a center wavelength of about 530±10 nm and a FWHM ofabout 40˜60 nm. In comparison, the second quantum dots 11 b may have alarger size than those of the first quantum dots 11 a in order toradiate red light having a relatively low energy. For example, thesecond quantum dots may have a center wavelength of about 625±10 nm anda FWHM of about 40˜60 nm.

Meanwhile, in the present exemplary embodiment, the blue light isconverted into the green light or the red light by the action of thefirst quantum dots 11 a or the second quantum dots 11 b. Further, theconverted light is scattered by the light diffusing agents 12 and thescattering-induced particles to be externally radiated from the colorfilter 100. Accordingly, the light is widely externally radiated and hasa uniform light gradation regardless of a position of a viewer.Accordingly, the color filter 100 having a wide viewing angle may beprovided.

As described above, the color filter 100 according to the exemplaryembodiment may minimize the luminous efficiency deterioration of thefirst layer 10 that serves as the light emitting layer and the filter,by including the second layer 20 that serves as the optical barrierlayer.

Hereinafter, a display device including the color filter in FIG. 2 willbe described with reference to FIG. 3. In an exemplary embodiment, aliquid crystal display device is described as an example of the displaydevice including the color filter, but the range of the exemplaryembodiment is not limited thereto, and the color filter may be employedin various display devices such as an organic light emitting diodedisplay, a light emitting diode display, or the like.

FIG. 3 illustrates a display device including the color filter of FIG.2.

Referring to FIG. 3, a display device 1000 according to the presentexemplary embodiment includes a light source 200, a lower display panel300, and an upper display panel 400.

The light source 200 may supply first light to the lower display panel300 and the upper display panel 400 in a first direction D1 of FIG. 3.The light source 200 may include an emitting body that emits the firstlight. For example, the first light emitted by the light source 200 mayhave a visible wavelength range, and may be light having high energy inthe visible wavelength range, e.g., blue light. As such, the blue light,which is the first light, may be supplied to the lower display panel 300and the upper display panel 400. However, the first light is not limitedthereto, and may be any light other than the blue light in the visiblewavelength range, or alternatively, may be ultraviolet light in anultraviolet wavelength range.

The light source 200 may include an emitting portion (not shown) thatincludes an emitting body and a light guiding plate that guides theemitted blue light toward the lower display panel 300. The emittingportion may be disposed at one side of the light guiding plate or may bedisposed below a lower surface of the light guiding plate.

The lower display panel 300 may include a first substrate 301 formed oftransparent glass, plastic, or the like, and a wiring layer 303 formedon the first substrate 301. The wiring layer 303 may include a thin filmtransistor (not shown) including a gate line, a storage voltage line, agate insulating layer, a data line, a source electrode, a drainelectrode, a semiconductor, a passivation film, and the like, and thethin film transistor thereof is connected to the gate line and the dataline. Meanwhile, a pixel electrode 304 is formed on the wiring layer303. The gate line, the data line, the source electrode, the drainelectrode, the semiconductor, and the pixel electrode may have variousstructures depending on exemplary embodiments.

The gate line and the storage voltage line are electrically separatedfrom each other, and the data line is insulated from and intersects thegate line and the storage voltage line. The gate electrode, the sourceelectrode, and the drain electrode respectively serve as a controlterminal, an input terminal, and an output terminal of the thin filmtransistor. The drain electrode is electrically connected to the pixelelectrode 304.

The pixel electrode 304 may be formed of a transparent conductivematerial such as indium tin oxide (ITO) or indium zinc oxide (IZO), andmay control an alignment direction of liquid crystal molecules bygenerating an electric field.

An alignment layer 501 is disposed on the pixel electrode 304. Thealignment layer 501 is a liquid crystal alignment layer includingpolyamic acid, polysiloxane, polyimide, or the like, and may include atleast one of generally-used materials. The liquid crystal molecules in aliquid crystal layer 500 may be initially aligned by the alignment layer501. The alignment layer 501 may be variously disposed depending onexemplary embodiments. The alignment layer 501 may be disposed at anupper side or a lower side of the liquid crystal layer 500, or may bedisposed at both of the upper side and the lower side of the liquidcrystal layer 500 as shown in FIG. 3. In some cases, the alignment layer501 may be omitted.

The liquid crystal layer 500 is formed between the lower display panel300 and the upper display panel 400. The thickness of the liquid crystallayer 500 may be in a range of, e.g., about 5 to 6 μm. The types of theliquid crystal molecules in the liquid crystal layer 500 and anoperation of the liquid crystal layer 500 may vary depending onexemplary embodiments. Specifically, the liquid crystal layer 500 may beinterposed between the first substrate 301 and the color filter 100 asshown in FIG. 3, or may be interposed between a second substrate 401 andthe color filter 100, depending on the operation thereof.

A first polarizing plate 302 is attached on a rear surface of the firstsubstrate 301. The first polarizing plate 302 may include a polarizingelement (not shown) and a passivation layer (not shown), and thepassivation layer may include tri-acetyl-cellulose (TAC). Alternatively,the first polarizing plate 302 may be interposed between the firstsubstrate 301 and the wiring layer 303 or may be disposed at anotherposition in the lower display panel 300.

A common electrode 404 is disposed on the liquid crystal layer 500. Thecommon electrode 404 may be formed of the transparent conductivematerial such as indium tin oxide (ITO) or indium zinc oxide (IZO), andmay control the alignment direction of the liquid crystal molecules bygenerating the electric field. However, the common electrode 404 may bedisposed variously depending on exemplary embodiments, or may bedisposed in the lower display panel 300.

The upper display panel 400 may include the second substrate 401 formedof transparent glass, plastic, or the like, and a second polarizingplate 402 disposed thereon. The second polarizing plate 402 may includethe polarizing element and the passivation layer, and the passivationlayer may include tri-acetyl-cellulose (TAC). In the present exemplaryembodiment, the second polarizing plate 402 is disposed on the secondsubstrate 401, but may be disposed at another position in the upperdisplay panel 400, for example, on the common electrode 404 or under thesecond substrate 401. In some cases, the second polarizing plate 402 maybe omitted.

The aforementioned color filter 100 is disposed under the secondsubstrate 401, and the color filter 100 is divided into the first regionPX1, the second region PX2, and the third region PX3 by the lightblocking members 403 as described above.

The light blocking members 403 may be formed of a light blockingmaterial including, e.g., metal particles of chromium (Cr), silver (Ag),molybdenum (Mo), nickel (Ni), titanium (Ti), tantalum (Ta), or the like,an oxide of the metal particles, or a combination thereof. The lightblocking members 403 prevent light leakage from the display device 1000and improve the contrast thereof. The light blocking members 403 aredisposed under the second substrate 401, and are spaced apart from eachother by a predetermined distance therebetween as shown in FIG. 3.

In the present exemplary embodiment, since the color filter 100 isthoroughly divided into each region by the light blocking members 403,the light introduced into one region is prevented from intruding intoanother region, thereby preventing color mixture between the red, green,and blue lights displayed by the display device 1000.

Meanwhile, the color filter 100 is disposed in front of the firstsubstrate 301. Specifically, the first substrate 301, the color filter100, and the second substrate 401 are sequentially disposed in front ofthe light source in the first direction D1 that is a supply direction ofthe first light.

In the present exemplary embodiment, the color filter 100 may bedisposed in the upper display panel 400, but it is not limited thereto.For example, the color filter 100 may be disposed in the lower displaypanel 300 depending upon an operation type of the display device 1000.

Herein, based on the first direction D1, the first layer 10 (e.g. 10 b,10 g, 10 r) is disposed in front of the second layer 20 (e.g. 20 g, 20r) in the color filter 100. In other words, as shown in FIG. 3, thecolor filter 100 has a structure in which the first light is introducedinto the green filter 10 g or the red filter 10 r, which are the firstlayer, through the green barrier layer 20 g or the red barrier layer 20r, which are the second layer.

As such, it is possible to provide the display device 1000 which canminimize the luminous efficiency deterioration of the first layer 10caused by the isotropic radiation characteristic of the quantum dots byadjusting a disposition direction of the color filter 100 such that thefirst light is introduced into the first layer 10 through the secondlayer 20.

Meanwhile, in a manufacturing process of the color filter 100 formed ofthe photosensitive material, the deterioration of the luminousefficiency of the quantum dots has been reported to occur in each of thephotolithographic processes such as exposure, development, baking, andthe like. However, in the case of the color filter 100 of theaforementioned exemplary embodiment, it is possible to manufacture acolor filter capable of minimizing luminous efficiency deterioration inthe photolithographic processes by forming a stacked body in which thesecond layer 20 that serves as the optical barrier layer is disposed onthe first layer 10 that serves as a filter layer in thephotolithographic processes.

Hereinafter, a method of manufacturing a color filter that minimizesluminous efficiency deterioration in a manufacturing process accordingto an exemplary embodiment will be described.

FIG. 4 is a flowchart showing the manufacturing method of the colorfilter of FIG. 2.

Referring to FIG. 4, the manufacturing method of the color filteraccording to the exemplary embodiment includes forming a light emittinglayer (e.g. first layer) on a substrate (S01), forming a barrier layer(e.g. second layer) on the first layer to obtain a stacked body in whichthe first layer and the second layer are stacked on the substrate (S02),pre-baking the stacked body (S03), exposing and developing (e.g.patterning) the stacked body to obtain the patterned stacked body (S04),post-baking the patterned stacked body (S05), and aging the stacked body(S06).

First, preliminary preparation includes preparing the substrate in whicha light blocking member is formed, preparing a photosensitive resin forforming the first layer, and preparing a photosensitive resin forforming the second layer.

In the preparing of the substrate in which the light blocking member isformed, light blocking members are disposed on the substrate formed ofglass, plastic, or the like, and are spaced apart from each other at apredetermined distance therebetween. The light blocking member is formedof materials including metal particles of chromium (Cr), silver (Ag),molybdenum (Mo), nickel (Ni), titanium (Ti), tantalum (Ta), or the like,oxides of the metal particles, or combinations thereof. Separate spacesformed by the light blocking members serve as a first region to a thirdregion.

In the preparing of the photosensitive resin for forming the firstlayer, a quantum dot-binder dispersed solution is prepared by mixing abinder and a chloroform dispersed solution of quantum dots (red orgreen) including a hydrophobic organic ligand at surfaces thereof.Herein, the quantum dots are uniformly dispersed in the quantumdot-binder dispersed solution.

Then, the photosensitive resin for forming the first layer ismanufactured by mixing the prepared quantum dot-binder dispersedsolution, a photopolymerization monomer, a photoinitiator, a lightdiffusing agent, a solvent, additives, and the like.

The photosensitive resin for forming the second layer is manufactured bymixing a photopolymerization monomer, a photoinitiator, a sensitizer, alight diffusing agent, a solvent, additives, and the like.

In step S01, the forming of the first layer, the photosensitive resinfor forming the first layer is spin-coated onto the substrate on whichthe light blocking member is formed. An amount of the region filled withthe photosensitive resin for forming the first layer may vary dependingon the operation of the display device, and the first region to thethird region may be partially filled therewith.

In step S02, the forming of the second layer, the photosensitive resinfor forming the second layer is spin-coated on the first layer.Accordingly, a stacked body including a double layer on the substrate,in which the first layer and the second layer are sequentially stacked,may be obtained.

In the pre-baking (S03), moisture existing in the first layer and thesecond layer is removed by pre-baking (PRB) the obtained stacked body.Specific conditions of the pre-baking such as temperature, time,atmosphere, and the like are already known and may be appropriatelyadjusted. In some cases, the pre-baking may be omitted. Through thepre-baking, a dispersed state of the quantum dots and the lightdiffusing agent in the stacked body from which the moisture is removedmay be changed.

In the exposing and developing (S04), the stacked body after beingcompletely pre-baked is exposed to light having a predeterminedwavelength using a mask including a predetermined pattern. Thewavelength and intensity of the employed light may be adjusted inconsideration of type and content of the photoinitiator and the quantumdots. Then, the exposed portions of the stacked body are developed usingan organic solvent, an alkali solution, or the like. Following completeexposure and development of the exposed portions of the stacked body,the unexposed portion of the stacked body is dissolved, and thepatterned stacked body in which the first layer and the second layer arestacked in a desired region may be obtained.

However, the luminous efficiency of the first layer is slightlydeteriorated in comparison with the luminous efficiency of the firstlayer prior to the exposure and development, because a dispersed stateof the quantum dots or the light diffusing agent in the first layer maybe altered during the exposure and development, or alternatively, lossof the quantum dots or the light diffusing agent may occur during theexposure and development process.

In the post-baking (S05), the patterned stacked body may be post-baked(POB) to improve crack resistance and solvent resistance. Thepost-baking may be conducted at a temperature of, e.g., about 150° C. toabout 230° C. for a predetermined time, e.g., about 10 min or more, orabout 20 min or more. As the post-baking is performed, physical andchemical characteristics of the first layer may be improved. However,the loss of the quantum dots and the light diffusing agent in the firstlayer may occur since heat is continuously applied thereto, so theluminous efficiency of the first layer may be slightly deteriorated.

In the aging (S06), the stacked body after being post-baked iscontinuously exposed to light having a weak intensity and apredetermined wavelength in order to stabilize an optical property ofthe stacked body. The specific conditions of the aging such aswavelength, intensity, exposure time, and the like may be appropriatelyadjusted. In some cases, the aging step may be omitted. The aging servesto improve the optical property of the stacked body, so the luminousefficiency of the first layer is slightly improved by the aging.

When the steps of S01 (the forming of the first layer) to S06 (theaging) are referred to as a unit process, the unit process may berepeatedly performed until all of the first region to the third regionare filled by using a step which determines whether all of the firstregion to the third region of the aforementioned color filter are filledor not (S07). If all of the first region to the third region have beenfilled, the unit processes have been completed. If not all of the firstregion to the third region have been filled, the unit process isrepeated.

However, in the present exemplary embodiment, a number of repeats of theunit process may vary depending on the kinds of the color filter and theoperation of the display device. For example, in the case that the colorfilter 100 illustrated in FIG. 2 is manufactured, since the first regionPX1 thereof is filled with the transparent body, one of the secondregion PX2 and the third region PX3 may be formed, and then the otherregion may be formed by repeating the unit process a single time.

The color filter manufactured by the above-described steps may minimizethe luminous efficiency deterioration during the processes. This isbecause all of the processes are performed after forming the secondlayer 20, which serves as a passivation layer on the first layer 10 thatserves as a light emitting layer, thereby physically and chemicallyprotecting the first layer 10 from heat during the pre-baking or thepost-baking steps, and from the solvent in the exposing and developingsteps, or the like.

Hereinafter, specific examples of the described technology will bedisclosed. However, the following examples are merely to exemplarilydescribe the described technology, so the range of the describedtechnology is not limited thereto.

EXAMPLES Example 1 [1] Preparing Quantum Dot-Binder Dispersed Solution

A quantum dot-binder dispersed solution is prepared by mixing chloroformin a dispersed solution including about 50 grams (g) of green quantumdots including oleic acid as a hydrophobic organic ligand at surfacesthereof, and about 100 g of a solution of a binder (propylene glycolmonomethyl ether acetate, PGMEA at a concentration of about 30 weightpercent (wt %)).

[2] Preparing Photosensitive Composition for Forming First Layer

A photosensitive composition for forming a first layer is prepared bymixing the quantum dot-binder dispersed solution prepared in step [1],about 100 g of hexaacrylate as a photopolymerization monomer, about 1 gof an oxime ester compound as a photoinitiator, about 30 g of TiO₂ as alight diffusing agent, about 10 g of pentaerythritoltetra(3-mercaptopropionate) as a curing agent, and about 300 g of PGMEAas a solvent.

[3] Preparing Photosensitive Composition for Forming Second Layer

The photosensitive composition for forming a second layer is prepared bymixing about 100 g of hexaacrylate as a photopolymerization monomer,about 1 g of an oxime ester compound as a photoinitiator, about 10 g ofpentaerythritol tetra(3-mercaptopropionate) as a curing agent, and about300 g of PGMEA as a solvent.

[4] Manufacturing Color Filter

The photosensitive composition for forming the first layer prepared instep [2] is spin-coated on a glass substrate, and then thephotosensitive composition for forming the second layer prepared in step[3] is spin-coated on the first layer. Accordingly, a stacked film isobtained, in which the substrate, the first layer, and the second layerare sequentially stacked. The obtained stacked film is pre-baked atabout 100° C. The pre-baked stacked film is exposed to light(wavelength: about 365 nm and intensity: about 100 mW) for about 1second (s), using a mask having a predetermined pattern, and then isdeveloped using a potassium hydroxide aqueous solution (concentration:about 0.043%) for about 50 s to obtain a pattern thereon. The stackedfilm on which the pattern is formed is post-baked three times, i.e.,first, second, and third post-baking, at about 180° C. at about 30 mintime intervals. The stacked film after the third post-baking is aged byexposing it to light (wavelength: about 450 nm, intensity: about 10miliwatts (mW)) for 24 hours (h). At a time point at which each step iscompleted, a blue light conversion rate and a blue light absorption rateof the stacked film are measured, and the measured results are listed inTable 1.

In this example, the blue light conversion rate designates an amount oflight converted to green light with respect to the amount of lightradiated to a stack, and the blue light absorption rate designates anamount of light remaining at the first layer or the second layer withoutreturning toward a light source with respect to the amount of lightradiated to the stacked body. The blue light conversion rate and theblue light absorption rate are represented by an amount of lightmeasured by a photometer (manufactured by Minolta Inc.) for a period ofabout 1 min.

Example 2

By executing identical steps [1] to [3] of Example 1, a photosensitivecomposition for forming a first layer and a photosensitive compositionfor forming a second layer are formed, and then the photosensitivecomposition for forming the first layer manufactured in the same manneras described in step [2] of Example 1 is spin-coated on a glasssubstrate, and the photosensitive composition for forming the secondlayer manufactured as described in step [3] of Example 1 is spin-coatedon the first layer. Accordingly, a stacked film is obtained, in whichthe substrate, the first layer, and the second layer are sequentiallystacked. The obtained stacked film is pre-baked at about 100° C. Thepre-baked stacked film is exposed to light (wavelength: about 365 nm andintensity: about 100 mW) for about 1 s using a mask having apredetermined pattern, and then is developed using a potassium hydroxideaqueous solution (concentration: about 0.043%) for about 50 s to obtaina pattern thereon. Then, omitting the post-baking step, the stacked filmon which the pattern is formed is directly aged by exposing it to light(wavelength: about 450 nm, intensity: about 10 mW) for 24 h. After eachof the above steps is completed, the blue light conversion rate and theblue light absorption rate of the film are measured, and the measuredresults are listed in Table 2.

Comparative Example

By executing identical steps as described in steps [1] and [2] ofExample 1, a photosensitive composition for forming a first layer isprepared, and then the photosensitive composition for forming the firstlayer prepared as described in step [2] of Example 1 is spin-coated on aglass substrate. Accordingly, a monolayer film is obtained, in which thefirst layer as a monolayer is stacked on the substrate. The obtainedmonolayer film is pre-baked, patterned (i.e. exposed and developed), andfirst, second, and third post-baked under identical conditions to thosedescribed in Example 1. Then, the blue light conversion rate and theblue light absorption rate of the monolayer film are measured after eachstep is completed, and the measured results are listed in Table 1.

Table 1 is as follows.

TABLE 1 Comparative Example 1 Example Pre-baking (PRB) Blue light 30 29conversion rate (%) Blue light 82 74 absorption rate (%) Exposure andBlue light 28 26 development conversion rate (%) (EXP & DEV) Blue light81 74 absorption rate (%) First post-baking Blue light 24 19 (POB1)conversion rate (%) Blue light 82 75 absorption rate (%) Secondpost-baking Blue light 21 17 (POB2) conversion rate (%) Blue light 83 75absorption rate (%) Third post-baking Blue light 22 15 POB3 conversionrate (%) Blue light 83 76 absorption rate (%) Aging (AGN) Blue light 26ND conversion rate (%) Blue light 82 absorption rate (%) POB1/PRB 80 65POB2/PRB 70 58 POB3/PRB 73 51 AGN/PRB 86 ND

In Table 1, in the case of the monolayer film of the ComparativeExample, an additional process such as further forming a passivationlayer or the like is needed to perform the aging step, so the aging isnot performed in the comparative example. Accordingly, items related tothe aging in the comparative example are listed as ND (“No Data”).

Further, in Table 1, the post-baking step in which a light conversionrate is most severely deteriorated, is performed continuously threetimes instead of repeatedly performing the pre-baking, the exposing anddeveloping, the post-baking, and the aging. As such, it is possible tosimulate a thermal environment that may be applied to a filter firstlyformed on the substrate when a filter is formed in each of the firstregion to the third region.

Referring to Table 1, in the case of the pre-baking as an initial step,blue light conversion rates are the same in Example 1 and theComparative Example, but the blue light absorption rate of Example 1 areabout an 8% higher value than that of the Comparative Example. Thismeans that, in the case of the Comparative Example, the luminousefficiency is deteriorated by evaporating the moisture or the like inthe first layer, which is the monolayer, in the pre-baking step.

The blue light conversion rates of Example 1 and the Comparative Exampleare deteriorated by a chemical environment where the exposure and thedevelopment are performed, but the blue light conversion rate of Example1 shows slower deterioration than that of the Comparative Example.

The blue light conversion rate of the Comparative Example is graduallydecreased by about 7%, about 2%, and about 1% in the first to thirdpost-baking steps, respectively. In total, the Comparative Examplegenerally shows a total luminous efficiency deterioration of about 10%.In contrast, the blue light conversion rate of Example 1 is decreased byabout 4% in the first post-baking step and about 3% in the secondpost-baking step, but is increased by about 1% in the third post-bakingstep. In total, Example 1 generally shows a total luminous efficiencydeterioration of about 6%.

Based on the results of Table 1, when the light conversion rate of thestacked body being post-baked with respect to that of the stacked bodybeing pre-baked is referred to as first retention, it can be seen thatthe first retention of Example 1 may be in a range of about 70% to about100%.

In contrast, in the case of being formed as the monolayer in theComparative Example, it can be seen that the first retention may be amaximum of about 65% or less. Therefore, it can be seen that the stackedstructure of Example 1, in which the second layer is further disposed onthe first layer, may effectively prevent the luminous efficiencydeterioration caused by heat.

Meanwhile, in the case of Example 1, an optical characteristic of thefirst layer may be improved by the aging. Accordingly, it can be seenthat the luminous efficiency after the aging step is increased by about4% in comparison with that after the third post-baking step. Further,when the light conversion rate of the aged stacked body with respect tothat of the pre-baked stacked body is referred to as second retention,it can be seen that the second retention of Example 1 may be in a rangeof about 85% to about 100%.

In contrast, in the case of being formed as the monolayer in theComparative Example, the additional step for forming the passivationlayer or the like after the post-baking step is required to perform theaging, and a total number of steps is increased, which may beundesirable in consideration of manufacturing efficiency.

Table 2 is as follows.

TABLE 2 Example 2 Pre-baking (PRB) Blue light 31 conversion rate (%)Blue light 78 absorption rate (%) Exposure and Blue light 31 developmentconversion rate (%) (EXP & DEV) Blue light 78 absorption rate (%) Aging(AGN) Blue light 36 conversion rate (%) Blue light 78 absorption rate(%) AGN/PRB 86

Referring to Table 2, for Example 2, in which the stacked body issubjected to the aging step after the patterning step without beingsubjected to the post-baking step, an excellent blue light conversionrate is shown.

For example, when the light conversion rate of the aged stacked bodywith respect to that of the post-baked stacked body is referred to asthird retention, the third retention may be in a range of about 100% toabout 120%.

Therefore, it can be seen that the luminous efficiency of Example 2 maybe improved similarly to that of Example 1 even though the aging step isdirectly performed without the post-baking step.

As described above, the luminous efficiency deterioration during themanufacturing process may be minimized when the color filter accordingto the exemplary embodiment is manufactured by performing thephotolithographic patterning process after forming the stacked bodyincluding the second layer which serves as the optical barrier layerdisposed on the first layer which serves as the light emitting layer.Moreover, the display device including the color filter as well as thecolor filter may be expected to show an improvement in luminousefficiency of the first layer due to the light-recycling caused by thesecond layer.

Consequently, according to the exemplary embodiment, it is possible toprovide a color filter and a display device including the color filterthat may minimize the luminous efficiency deterioration which occursduring the manufacturing process and maintain the excellent luminousefficiency after the manufacturing process.

While this disclosure has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A color filter comprising: a first regionconfigured to emit a first light; a second region configured to emit asecond light having a longer wavelength than a wavelength of the firstlight; a third region configured to emit a third light having a longerwavelength than the wavelength of the second light; a first layercomprising a quantum dot; and a second layer disposed on at least onesurface of the first layer, wherein the first region, the second region,and the third region are spaced apart from each other by a predetermineddistance, wherein the first layer is disposed to correspond to at leastone of the second region and the third region, and the second layer isdisposed to correspond to at least one of the second region and thethird region, except for the first region, and wherein the second layerhas light transmittance of greater than or equal to about 80 percentwith respect to the first light.
 2. The color filter of claim 1, whereinthe first layer is disposed to correspond to the second region and thethird region, except for the first region.
 3. The color filter of claim1, wherein the first layer which corresponds to the second region andthe first layer which corresponds to the third region are spaced apartfrom each other.
 4. The color filter of claim 1, wherein the quantum dotcomprises a first quantum dot, and a second quantum dot which emitsdifferent light to the first quantum dot.
 5. The color filter of claim4, wherein the first quantum dot is disposed in the first layer whichcorresponds to the second region, and the first quantum dot isconfigured to emit the second light having a longer wavelength than thewavelength of the first light by absorbing the first light.
 6. The colorfilter of claim 5, wherein the second light having a center wavelengthin a range of 520 nm to 540 nm, and a full width half maximum in a rangeof 40 nm to 60 nm.
 7. The color filter of claim 4, wherein the secondquantum dot is disposed in the first layer which corresponds to thethird region, and the second quantum dot is configured to emit the thirdlight having a longer wavelength than the wavelength of the first lightby absorbing the first light.
 8. The color filter of claim 7, whereinthe third light having a center wavelength in a range of 615 nm to 635nm, and a full width half maximum in a range of 40 nm to 60 nm.
 9. Thecolor filter of claim 1, wherein the first light is blue light.
 10. Thecolor filter of claim 1, wherein a thickness of the second layer is in arange of about 10 percent to about 60 percent of a thickness of thefirst layer.
 11. The color filter of claim 1, wherein each of the firstlayer and the second layer comprises a photosensitive resin.
 12. Thecolor filter of claim 1, wherein the first layer further comprises alight diffusing agent selected from a metal oxide particle, a metalparticle, and a combination thereof.
 13. The color filter of claim 1,wherein the quantum dot comprises a Group II-VI compound, a Group III-Vcompound, a Group IV-VI compound, a Group IV compound, a Group II-III-VIcompound, a Group I-II-IV-VI compound, or a combination thereof.
 14. Thecolor filter of claim 1, wherein the first region comprises atransparent body.
 15. The color filter of claim 1, wherein the colorfilter receives the first light from a light source in a firstdirection, and wherein in the color filter the first layer is disposedin front of the second layer in the first direction.
 16. A displaydevice comprising: a color filter comprising: a first region configuredto emit a first light; a second region configured to emit a second lighthaving a longer wavelength than a wavelength of the first light; a thirdregion configured to emit a third light having a longer wavelength thanthe wavelength of the second light; a first layer comprising a quantumdot; and a second layer disposed on at least one surface of the firstlayer, wherein the first region, the second region, and the third regionare spaced apart from each other by a predetermined distance, andwherein the first layer is disposed to correspond to at least one of thesecond region and the third region, and wherein the second layer haslight transmittance of greater than or equal to about 80 percent withrespect to the first light; a light source configured to emit the firstlight in a first direction; a first substrate disposed in front of thelight source in the first direction; the color filter disposed in frontof the first substrate in the first direction; and a second substratedisposed in front of the color filter in the first direction, wherein inthe color filter the first layer is disposed in front of the secondlayer in the first direction.
 17. The display device of claim 16,wherein the quantum dot comprises a first quantum dot, and a secondquantum dot which emits different light to the first quantum dot. 18.The display device of claim 17, wherein the first quantum dot isdisposed in the first layer which corresponds to the second region, andthe first quantum dot is configured to emit the second light having alonger wavelength than the wavelength of the first light by absorbingthe first light.
 19. The display device of claim 18, wherein the secondlight having a center wavelength in a range of 520 nm to 540 nm, and afull width half maximum in a range of 40 nm to 60 nm.
 20. The displaydevice of claim 17, wherein the second quantum dot is disposed in thefirst layer which corresponds to the third region, and the secondquantum dot is configured to emit the third light having a longerwavelength than the wavelength of the first light by absorbing the firstlight.
 21. The display device of claim 20, wherein the third lighthaving a center wavelength in a range of 615 nm to 635 nm, and a fullwidth half maximum in a range of 40 nm to 60 nm.
 22. The display deviceof claim 16, further comprising a first polarizing plate disposed infront of the first substrate in the first direction, and a secondpolarizing plate disposed in rear of the second substrate in the firstdirection.
 23. The display device of claim 16, wherein the displaydevice is at least one of a liquid crystal display device, an organiclight emitting diode display device, or a light emitting diode display.24. The display device of claim 23, wherein the display device is theliquid crystal display device, and the display device further comprisesa liquid crystal layer interposed between the first substrate and thecolor filter or between the color filter and the second substrate.